Support Galera Replication

[FrederikNJS]

To use this docker image in production, it would be very nice to be able to run it with replication, to maintain some redundancy.

The bitnami/mariadb image already does this, but they don't have the 10.x versions.

[yosifkit]

Would Galera cover that for you (#24) or are you looking at the autoconfiguration that is in their script (https://github.com/bitnami/bitnami-docker-mariadb/blob/master/rootfs/bitnami-utils-custom.sh)?

[krasi-georgiev]

I am on the same path

mariadb has this build it from 10.1 and after
this is resolved #29
it would be nice to implement some sort of env to bootstrap only the first time the container is lunched using the mysqld --wsrep-new-cluster and then any additional container can join the cluster
with mysqld --wsrep_cluster_address=gcomm://container_name

[nazar-pc]

If anyone is interested - this is not very straightforward, but doable.
You can find scalable MariaDB image that requires no configuration here: https://github.com/nazar-pc/docker-webserver
Please, read readme and advanced documentation carefully, it really works well.
I'm working on GlusterFS image, so that literally everything will scale with zero configuration, but MariaDB works fine already.
Comparing to Bitnami's images my images look a bit simpler and uses this MariaDB official image as base image. Take a look and let me know what you think.

BTW, I'm not sure that that PR with Galera support is really as good as it could be. Also I have such feeling, that official image should not provide Galera setup, it is tricky and will not be flexible enough eventually. Current image is good enough and contains most of necessary basic blocks to build Galera image yourself while nicely reusing what is done here already.

[krasi-georgiev]

thanks I will check it.

I will not advise you to go for the GlusterFS , especialy for web apps. I haven't tested it myself , but the feedback is that is quite slow for when accessing many small files.

I have setup 2x lsyncd container and so far it syncs really well. It is kind of a rsync daemon , watches for changes and it fires rsync

The documentation sais not fit for 2 way sync , but in my setup it works very , very well.

Here is the repo, It is not universal but you don't have time right now to improve it.
https://github.com/vipconsult/dockerfiles/tree/master/lsyncd

I start is with the same compose file on both hosts

lsyncd:
# so that can increase fs.inotify.max_user_watches
privileged: true
# without net host it cannot bind to the internal ip
net: host
volumes:
# share the same keys on all containers so that no ssh config is needed
- ../lsyncd/.ssh:/root/.ssh
# the actual folders that will be synced
- /folder1ToShare:/sync/f1
- /folder2ToShare:/sync/.f2

it needs 2 env variables
$INTERNAL_IP - ot binds to this ip
$LB_SERVER - it connects to this ip on port 222

on host 1
$INTERNAL_IP - 172.0.0.10
$LB_SERVER - 172.0.0.20

on host 2
$INTERNAL_IP - 172.0.0.20
$LB_SERVER - 172.0.0.10

[macropin]

If you're going to support Galera, please be sure to include galera-arbitrator-3 (aka garbd) in future builds.

[activatedgeek]

The current 10.x builds already have the Galera plugin. Doesn't that work? I have been trying to debug that for quite a while now and the second node after the bootstrap node crashes saying MySQL init process failed. Here is an SO post for anybody who knows about the issue: http://stackoverflow.com/questions/39744949/unable-to-create-mariadb-galera-cluster.

[klausenbusk]

The current 10.x builds already have the Galera plugin. Doesn't that work? I have been trying to debug that for quite a while now and the second node after the bootstrap node crashes saying MySQL init process failed.

I have been using the MariaDB 10.1 with Galera for a long time (3+ months) and it works perfect..
Before that I used a home crafted image with MariaDB Galera (before it was merged into regular MariaDB)
I start it as:

/usr/bin/docker run \
        --name mariadb-galera \
        --rm \
        -p 3306:3306 \
        -p ${COREOS_PRIVATE_IPV4}:4444:4444 \
        -p ${COREOS_PRIVATE_IPV4}:4567:4567/udp \
        -p ${COREOS_PRIVATE_IPV4}:4567-4568:4567-4568 \
        --dns 172.17.42.1 \
        -v /var/lib/mysql:/var/lib/mysql \
        -v /var/log/mysql:/var/log/mysql \
        mariadb:10.1 \
        --log-bin=mysqld-bin \
        --log-slave-updates \
        --binlog-format=row \
        --binlog-annotate-row-events \
        --innodb-autoinc-lock-mode=2 \
        --innodb-flush-log-at-trx-commit=0 \
        --slow-query-log \
        --wsrep-on="ON" \
        --wsrep-log-conflicts \
        --wsrep-slave-threads=4 \
        --wsrep-provider="/usr/lib/libgalera_smm.so" \
        --wsrep-cluster-address="gcomm://mysql.skydns.local,mysql.skydns.local" \
        --wsrep-node-address="${COREOS_PRIVATE_IPV4}" \
        --wsrep-node-name="%H" \
        --wsrep-sst-method="xtrabackup-v2" \
        --wsrep-sst-auth="${SST_AUTH}"

I run it on a CoreOS cluster with Skydns, and the server register itself with Skydns/etcd so it is available on "mysql.skydns.local"..

[activatedgeek]

@klausenbusk Would you mind quickly reviewing the configs present at the SO link I have provided? http://stackoverflow.com/questions/39744949/unable-to-create-mariadb-galera-cluster

[klausenbusk]

@klausenbusk Would you mind quickly reviewing the configs present at the SO link I have provided? http://stackoverflow.com/questions/39744949/unable-to-create-mariadb-galera-cluster

First you should use 10.1, secondly it doesn't seems like you expose any ports?, thirdly you need to set --wsrep-node-address.. :)

[activatedgeek]

@klausenbusk I am using inter-container networking so I don't think port exposure is needed. I am trying to run it on my local machine, I can worry about multi-host communication later. Also --wsrep-node-address is it necessary? According the logs of second node, it looks like the SST was completed successfully. Thanks! :)

[klausenbusk]

@activatedgeek Oh yes, I think you correct :)
Do you have a full log of the secondary node?

[activatedgeek]

@klausenbusk Have a look here: http://pastebin.com/3exPpqvc. If you have a look at lines 215-217 you can see that the SST was completed successfully, but the node crashed due to failed init. Also line 220 shows port: 0, which is rather odd as on the bootstrap node it shows port: 3306.

[klausenbusk]

@klausenbusk Have a look here: http://pastebin.com/3exPpqvc. If you have a look at lines 215-217 you can see that the SST was completed successfully, but the node crashed due to failed init. Also line 220 shows port: 0, which is rather odd as on the bootstrap node it shows port: 3306.

The issues is that the image get stuck in the initializing phase (which is running with --skip-networking (explain port 0)).
That the reason why I run mkdir -p /var/lib/mysql/mysql, before I start MariaDB, so It doesn't run the initializing code.

So try something like:

mkdir -p /var/lib/mysql/mysql
docker run --rm -e MYSQL_ROOT_PASSWORD=123 \
  -v /var/lib/mysql:/var/lib/mysql \
  activatedgeek/mariadb:devel \
  --wsrep-cluster-name=test_cluster \
  --wsrep-cluster-address=gcomm://172.17.0.2,172.17.0.3,172.17.0.4

[activatedgeek]

@klausenbusk So essentially, you mean that start all nodes such that the folder /var/lib/mysql (or the data dir) should contain a mysql folder? This could either be done within the container or the mounted volume. Is that right?

[klausenbusk]

@klausenbusk So essentially, you mean that start all nodes such that the folder /var/lib/mysql (or the data dir) should contain a mysql folder? This could either be done within the container or the mounted volume. Is that right?

Correct expect for the bootstrap node, also you should consider using xtrabackup for SST.